How Does An Email Server Work? Everything that comes about on the internet is through the client - server communication. A client is any computer tied in to the internet through a internet protocol (IP) address. A server is a different computer linked to the internet and does the chore of hosting and servicing web pages and causes the email system. Servers are actually computer programs that run on high speed machines. These machines are designed to handle the requests of millions of clients at a time who access a webpage or email service which they are using on their machine. simply this process is called web hosting.

But How Does An Email Server Work? An email system is made possible by two types of servers. One is the SMTP server and other is the POP3 or IMAP sever. Several of us use a mail client software like Microsoft Outlook or Mozilla Thunderbird that transfers the incoming email on your PC, from the mail server of the email account you use with your ISP.

SMTP Email Server

SMTP stands for 'Simple Mail Transfer Protocol'. A protocol is an algorithm or function of communication, for a detailed purpose. This server program entirely handles the sending part of a mail. When you login to your mail account through a mail client or through a site like gmail, your client computer communicates with the SMTP host of your email site. An email is in this format 'name@domainname.com'.

The SMTP server receives the email through port 25, 80, 587 or 2626. Different ports of a server machine are assigned by the server admin. Then the SMTP server separates the user name and the site name. If the site name is the same as the mail site from which it is sent, then it forwads the mail to its POP3 or IMAP server, which handles incoming mail.

If the sent email belongs to a different site like hotmail then the gmail SMTP server will contact the DNS (Domain name server) and ask for the IP addresses of thehotmail server and forward the mail to the hotmail SMTP server. An email is a text file which is then sent on by the hotmail SMTP server to its POP3 or IMAP server. This server stores it into a special file committed to the receivers mail account.

IMAP and POP3

The POP3 server covers the other end of the emailing chore. POP stands for 'Post Office protocol'. Through the server port 110, the POP3 server receives your request for reading mail after you log in.Gmail's POP3 server, conserves a elaborate text file for every account that is recorded on it. All the mail messages delivered through the SMTP server communication are writen in that text file, one after the other along with all the required delivery timing and other information. When you want to read the mail, it dissects the text file and breaks up each mail by header, subject and sender's name and processes it on your machine. The only disadvantage of a POP3 server is that once you download all your incoming messages through a mail client, they do not stay on the server.

The IMAP (Internet Message Access Protocol) server is an improvement of POP3 server and takes care of the only disadvantage it has. What it does is, it keeps the original copy of your incoming mail text file on the server, even when you have download it. So with an IMAP server, you can access your mail from any PC and download the mails on the PC or read them on the site itself, without downloading.